"""
203. 移除链表元素
给你一个链表的头节点 head 和一个整数 val ，请你删除链表中所有满足 Node.val == val 的节点，并返回 新的头节点 。
示例 1：
输入：head = [1,2,6,3,4,5,6], val = 6
输出：[1,2,3,4,5]

示例 2：
输入：head = [], val = 1
输出：[]

示例 3：
输入：head = [7,7,7,7], val = 7
输出：[]
"""
#Definition for singly-linked list.
class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next
class Solution:
    def removeElements(self, head:ListNode, val: int) -> ListNode:
        dummy_head = ListNode(next=head)
        cur = dummy_head
        while cur.next != None:
            if cur.next.val == val:
                cur.next = cur.next.next
            else:
                cur = cur.next
        return dummy_head.next

if __name__ == '__main__':
    a = ListNode(1)
    b = ListNode(2)
    c = ListNode(3)
    d = ListNode(4)
    e = ListNode(3)
    a.next = b
    b.next = c
    c.next = d
    d.next = e
    ss = Solution()
    rr = ss.removeElements(a,3)
    while rr.next != None:
        print(rr.next.val)
        rr.next = rr.next.next

